Technical Field
The present invention relates to an image processing device, an imaging device, an image processing method, and an computer readable medium.
Related Art
Digital cameras are widely known that are provided with autofocus, in which phase difference detection methods and contrast detection methods are employed, and also what is referred to as a manual focus mode, in which a user can manually perform focus adjustment.
Digital cameras including a manual focus mode are known in which a reflex mirror is provided to enable focus adjustment while checking an imaging subject, and a method is utilized in which a split microprism screen is employed to display the phase difference visually. Utilization of a method in which contrast is checked visually is also known.
However, in digital cameras with the reflex mirror omitted that have become prevalent in recent years, since there is no reflex mirror, there is no method to check the subject-image while displaying the phase difference, and contrast detection methods have had to be relied on. However, in such cases, contrast cannot be displayed at a resolution greater than that of a display device, such as a Liquid Crystal Display (LCD), requiring adoption of methods such as enlarging a portion for display.
In recent years, therefore, a split-image is displayed within a live-view image (also referred to as a through image), so as to make the work of focusing on the imaging subject easier for the user when in manual focus mode. Split-image used herein refers to a divided image that has been divided into two, for example (such as respective images divided in the up-down direction) in which displacement is imparted in a parallax generation direction (such as the left-right direction) according to focus misalignment, and is a split-image in which the displacement in the parallax generation direction disappears in an in-focus state. An operator (such a photographer) operates a manual focus ring to focus so that the displacement in the split-image (such as respective images divided in the up-down direction) disappears.
In the imaging device described in Japanese Patent Application Laid-Open (JP-A) No. 2009-147665, out of light rays from an imaging optical system, a first subject-image and a second subject-image formed by light rays divided by a pupil divider are each photoelectrically converted to generate a first image and a second image. The first and the second images are employed to generate a split-image, and a third subject-image formed by light rays not divided by the pupil divider is photoelectrically converted to generate a third image. The third image is displayed on a display and the generated split-image is displayed inside the third image, and color data extracted from the third image is applied to the split-image. By applying color data extracted from the third image to the split-image in this way, excellent visual checkability of the split-image can be achieved.
Moreover, due to the low display resolution of an electronic viewfinder of a camera and a display (for example an LCD) provided on the back face side of a camera, it is difficult to adjust focus accurately to the perfect focus position (the position where the imaging lens is in the focused state) while viewing a split-image. There is a proposal for a method to utilize dependency of the displacement-amount in the parallax generation direction of the split-image on parallax, to assist focusing adjustment by a user by emphasizing the parallax. Such a method enables more intuitive confirmation by a user of the amount of how much deviation there is from in-focus by using the split-image.